In XCOM: Enemy Unknown, the human race was forced to react to an invading alien menace. We needed to quickly build up our resources and communications capabilities, train troops, and develop new technologies to combat enemy forces. We lost that war.
XCOM 2 is, in many ways, a reflection of its predecessor’s approach. Humanity is mobile and proactive. It’s up to players to take the fight to the aliens and their human collaborators, and you don’t have the world’s backing or its plentiful resources at your disposal.
Tactically, the humans’ best play is guerrilla warfare as opposed to an overt show of force. This means you need to stay mobile and recapture areas of the globe by cultivating resistance cells.
Since players no longer have a fixed base, the Avenger mobile command center now serves as headquarters. The ship can can be outfitted like the old Enemy Unknown bunker. Players need to reclaim parts of the alien derelict to bolster research and engineering, train soldiers for specific specialties, and develop ammunition and explosives appropriate for the tasks at hand. Each room can be assigned a non-combat member of the resistance. Effects include speeding up research or manufacturing, or getting a wounded soldier back into battle earlier than expected.
Because you don’t have a bank account fed by the world’s nations, you have to rely on other resources to accomplish your missions. These include intel and precious time. Intel is used to make connections with resistance cells and take on missions to liberate segments of the globe. You can also use your resources to purchase technologies from the black market. If you happen to fall behind in R&D, you can catch up via this alternate path, but it’ll cost you.
XCOM 2’s strategy layer should feel familiar to anyone that played Enemy Unknown, but it’s been changed to fit the sequel’s theme. The mobile base gives players a chance to react to the changing world around them, supportnascent cells, and take the fight to Advent before all is lost.